What does happy really mean?

These days,I was thinking about a question:am I happy now?I do not know.This question reminds me of a same question our English teacher asked us:What does happy mean to you?I still remember that my mind was empty when my teacher asked this question.Unfortunately,she called my name and asked me to make a impromptu speech at the platform in front of my whole classmates.I was embarrassed then because I really don't know what say.Forgotten to say hi to everybody before I began my speech:
"In my mind,happy is simple.For me,funny stuffs can make me happy..."
I didn't say much words before I got down.And my teacher seems unhappy for my behavior.Maybe she was stocked that I hardly had any deep feeling about happiness.
After the recovery of my ailment,I start to know that happy means different to different people under different circumstances.Happiness is some kind of abstract feeling.A man of healthy will never feel the happiness of being a health man,but a patient just recovered can;Someone who live with his parents will never feel the happiness of being unite,but someone who just stay with their parents one or two days a year can;A fat feel happy to become slim;A poor feel happy to be rich,etc...
For me,right now,I would be happy if I had my paper published successfully.